.nav-bar {
  display: flex;
  height: 70px;
}

.nav-item {
  display: flex;
  justify-content: center;
  align-items: center;
}

.nav-left  {
  width: 40px;
  background-color: red;
}

.nav-right {
  width: 50px;
  background: gray;
}

.nav-center {
  flex: 1;
}